Growing organic vegetables in Greenhouses

With a long wet season and a pretty hot summer, its often tempting to grow vegetables in a more insulated/protective environment – ergo a green house. But growing in such an environment is  different enough from our usual organic approaches while growing in the field to give us some pause.

For example, while its probably easier to prevent insects and other fungal/bacterial diseases from getting to your crops, other beneficial ones probably get eliminated too. Also, maintaining good air circulation within the greenhouse can present an interesting challenge in our climates. Also, there is the cost of the green-house to consider, along with the fact that it needs to fit our needs in two very different seasons – summer and monsoon.

From our visits to a few organic green-house projects (in Pune and Coimbatore), we’ve been able to observe the following:

  1. Indian greenhouses seem to be plastic+shadenet combo structures which shelter plants considerably from wet and hot weather
  2. They are very carefully insulated from any external pests, with care taken while entering and leaving the interior
  3. Most growers seem to have little use for the sprinklers and have adopted drip-irrigation for their watering needs
  4. Timely and regular sprays of neem and other preventive organic pest repellents seem critical to a pest-free environment
  5. Strangely (for us), there is less emphasis on crop diversity than we practice on our fields
  6. Certain vegetable varieties seem to be better suited to greenhouses (not sure how)
  7. Providing nutrition through the drip system seems to work well for greenhouse growers

 

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Hardening saplings for transplanting

For most farmers and gardeners, there is only one thing more discouraging than the failure of seeds to germinate — and that’s the failure of transplanted saplings to survive the process.Young saplings tend to be badly hit, especially when the weather is on the hotter side, and just wilt to death in a couple of days after transplanting.

But this is entirely avoidable if we accept a few basic principles:

  1. The problem is caused primarily because the plant is unable to adapt to a new situation
  2. We need to use the instinct of self preservation (present in almost any living thing) to assist us
  3. We may need to ‘protect’ the sapling in its early days after the transplanting

Our experience is that plants that are systematically hardened before transplanting consistently achieve over 90% survival rates. The trick is to plan your dates of transplanting, and not just do a transplant when time permits. All transplanting on our farms is done in the late afternoons, so that the plants have time to recover overnight without excessive loss of moisture. But the preparation of the saplings actually begins about a week earlier (ideally).

Here is how it (ideally) goes:

  1. A week before we begin reducing the amount water provided to the saplings (drop by 25% on D-7 and again by 25% on D-5)
  2. Water the saplings on D-2 which is about 48 hours before transplanting (about half of what was being provided before D-7) and don’t water again till its almost transplanting time
  3. Just 30 minutes before transplanting, you should water the saplings very well. Ensure that the roots are not damaged by pulling them out gently
  4. If the weather is really warm, its a good idea to set up a shade net (50%) to protect saplings till they have recovered

Hardening_Transplants

NOTE: If you can retain the soil around the roots, it helps. Put in a fist-full of compost in the pit where you will transplant. Transplanting is also a good time to treat the saplings with panchagavya* (growth promoter) and trichoderma** (protection against fungal disease).

Lastly, be a little patient and wait for a week before giving up on shocked saplings. Often they will recover even though they look extremely poor for the first few days. Put some dry mulch or leaves around every sapling so leaves don’t touch the soil directly. This prevents leaves from rotting and at the same time the roots are protected from direct sun and loss of moisture.

* Treating with Panchagavya: Dip sapling roots in 3% panchagavya for about 3 minutes just before the transplant

** Treating with trichoderma virde: Dip sapling roots in trichoderma solution prepared by putting 1tbsp of the powder in a litre of water. Remember to mulch the beds to protect the beneficial trichoderma fungus from direct sunlight

 

Why use raised beds?

Raised beds are a common feature across all our vegetable gardens and farms, and we often have full time farmers question the wisdom of creating these beds for various reasons.

Sometimes, in sandy soil, they feel that this results in excessive water requirements because the water settles at the bottoms of the beds. In other cases, we’ve had it pointed out that the effort that it takes to make them is not worthwhile when planting at ground level works as well.

Freshly made 6-8″ raised beds of 3′ width with 1′ walking paths

Our reasons for sticking with raised beds are both functional and aesthetic.

  1. Primarily we do this because our fields are the low-lying variety, and are inundated through the monsoon. This results in the presence of water till quite late and we’re worried that the excessive presence of water in the young plants will result in disease. By raising our beds we are insuring ourselves against this and allowing our planting to begin a little earlier.
  2. The visual order that these beds bring to our farms appeals to customers and clients who visit, partly because it appeals to their urban sensibilities and also because it becomes easier for them to figure out where not to step.
  3. It also allows for a little extra depth of loosened soil for our root vegetables which we have found results in better growth and less work in terms of having to pile up soil for carrots or radish that pop out of the soil.

The height of our raised beds varies according to the nature of the soil in the fields in question. In soft sandy soils we start out with beds raised about 5-6″ and these settle to about 4″ after some time. In more loamy soils we would have beds raised to 6-8″ levels and if the field is particularly low lying (ie. the water table is really close to the surface), we will raise it as much as 10-12″ high.

The width of the beds is usually 2.5′ wide so that you can reach across for weeding, sowing in watering instead of having to walk around to the other side. The walking paths are typically a foot wide, to allow for squatting comfortably especially when you are weeding or harvesting. However, if efficient use of the land area is required you can make beds of upto 4′ width so that the area lost to the walking paths in between is minimised.

A good tip we’ve learned to increase the watering efficiency is to create a raised border on the beds to keep the water in, so it doesn’t spill over the edge into the walking paths. This needs to be reinforced from time to time as it gets eroded. Covering empty space with straw mulch is another way to be more water efficient.

The length of our raised beds is usually 25-30 feet, but we’ve gone as long as 27 metres in a larger field.

You can of course choose to avoid raised beds, if you feel that it isn’t affected by the problems we have described above.

 

 

 

Growing Lettuce in Warmer Conditions

Heat is the primary concern for growing lettuce, and can affect your efforts from the germination stage through the harvest. Ideally, temperatures of about 18-22˚C is when lettuce grows well in the western coast of India, but with a little care you can compensate for conditions of approximately 25-30˚C which are predominant in the winter along India’s western coast.

Growing lettuce in cool temperate conditions is pretty easy, but when you are in warm humid conditions like Goa, this king of salad leaves needs some extra care

salad-bowl-lettuce

Figure 1: Lettuce can grow very well in Goa

 

CHOOSE THE RIGHT VARIETIES
First, select the right varieties of lettuce to grow – heading lettuces like iceberg are a very long shot. Instead focus your attention on the leaf lettuces and romaine lettuces. Some varieties are more heat tolerant than others and you will need to check that their seeds are easily available in India too.

We’ve found the following varieties more productive in Goa’s conditions and seeds possible to source too (check with Annadana Seed Savers, Bangalore)…

  1. Salad bowl (green)
  2. Red salad bowl
  3. Grenoble red (Rouge grenoblaise)
  4. Deer tongue
  5. Marvel of 4 seasons

To begin with, you should germinate your lettuce in semi shade conditions, so that germination is not badly affected by the hot sunlight. The optimum temperature for lettuce is less than 20˚C, so you should expect germination to be in the 60% range if you are planting early at about 25˚C (before the cooler weather occurs).

CAREFUL WITH YOUR NURSERIES
You need to take care that the soil in your nursery beds or pots is really well prepared – soft loamy soil, well drained by using sand or coco soil and old compost that is well decomposed should be used. Do not cover with too much soil, just 2-3mm is fine and do not over water. A fine layer of moss on the soil means that over watering is occurring, and cracks in the soil surface mean that it’s probably too clayey.

Usually the lettuce seeds take 3-5 days to germinate and will have light green leaves. Once the germination happens, the lettuce saplings need more sunlight for at least 3-4 hours in the morning. If they don’t get this, they will tend to become lanky and will tend to be weaker and susceptible to excessive shock while transplanting. Evening sunlight is usually harsher so try and plant in a way that your beds are protected then.

Regulate the sunlight availability for the saplings by either moving your pot nursery or by removing the shade net from beds (making your shade net flaps easily removable is a great idea. Purchase the 50% variant of shade net for use your lettuce bed nurseries and for when the final transplanting will happen in beds.

Figure 2: Lettuce saplings ready for transplant

 

PREPARE SAPLINGS FOR TRANSPLANT
Prepare the saplings for transplanting by reducing the watering by 20% from day 15 onwards, and then don’t water for 48 hours before the transplant. Just 30 minutes before you pull them out; water them very well so that they can stock up on water.

Transplanting should always be done about 21-25 days from sowing, at the 4-5 leaf stage and when the sun is low in the evenings (after 4 PM). This substantially increases the chances of the lettuce surviving the heat of the day without going limp. It’s a good idea to mulch your well manured raised beds with dry straw before transplanting, but make sure that you create a gap in the straw to prevent contact with the transplanted sapling.

Scoop out a shallow basin of soil in the beds, and put in a handful of manure before you transplant the sapling in. This allows water to be soaked in better into the roots without soaking the leaves excessively.

Provide shade with a shade net for the first 5-6 days until the transplanted saplings have recovered from the shock (leaves aren’t looking limp anymore and the plant is looking healthy). The kind of structure that you choose to use will depend on the direction of the sun.

Figure 3: Shade net can help protect newly transplanted saplings from heat

Once this stage has been passed the lettuce plants will usually grow well unless it gets unusually warm.

In case you have a problem with caterpillars or grasshoppers you can spray either a neem oil or cow urine spray (5% diluted solution in water). Make sure that this is done at least a week before you are harvesting.

To download this as a printable PDF, click here

(c) Prepared for Growing Vegetables Organically 2013 Edition by Miguel Braganza and Green Essentials.

Steady, sustainable soil improvement

With the focus being firmly on the soil in organic farming, we’ve found that soil improvement is one of the primary challenges facing most home gardeners in Goa. Some have lateritic soil that produces less than desirable results, others lose soil fertility because of either not managing it well or because of erosion in the monsoons.

Green Manuring is a process of growing certain crops on your land or in your garden in order to improve soil fertility. It consists of growing mainly leguminous crops that are known to fix nitrogen into the soil as they grow. In addition, other seeds are also grown so that they can add bio-mass into the soil, which on decomposing also improves soil fertility and texture.

While there are many approaches to green manuring, we’d adopted the one described here as a semi-quick fix for poor soil – and had pretty good results with it. Our experience has been that there are substantial, visible improvements in organic content, nitrogen addition, soil texture and even microbial health (indirectly) as a result of just 2 cycles of this procedure over four months.

Most importantly its not too labour intensive, relatively inexpensive and if done at the right time (late-May, early June) the monsoon does most of the work for you.

Here is where you can find a detailed set of instructions (PDF)

 

What we try to do: Designing a farm

Sometimes, its easier to have someone else describe what you’re trying to do, and Anjali does a much better job of it on her blog than we ever have.

“…Among other experiments, they will be doing a lot of cross-planting where different types of plants are grown  in close proximity to compliment each other. They are also experimenting with high-density farming, which is a way to plant a few samplings of fruit trees in close proximity…”

Follow the linkhttp://www.newyorkgoadiaries.com/2012/11/organic-farming-yogi-farms.html

 

How to protect against pests without poison

Any farm faces problems due to pests or diseases from time to time. But the practices followed to deal with these situations vary greatly. Our solution is to concentrate on soil health and prevention, and occasionally use organic/natural cures.

Preventive practices

  1. Use manure liberally (after ensuring that its well decomposed) for healthier and more disease resistant plants
  2. Don’t grow large areas of the same crop (or same families) together, different crops in adjacent beds
  3. Protect against fungal diseases (fusarium wilt) by treating manure with trichoderma virde and also treating saplings in trichoderma solution when transplanting
  4. Protect against aphids by planting trap crops – that also attract ladybirds (white and yellow flowers)
  5. Protect against nematodes by waiting till soil dries out and then using marigold planted every 2m
  6. If you can, try and find the right species of trichogramma wasps to eliminate caterpillars
  7. Add wood ash to the manure/soil while preparing beds so that pests avoid settling there
  8. Destroy any plants affected by viral diseases (like leaf mosaic virus)
  9. Select varieties that have better disease resistance for diseases you have concerns about

Cures, for Emergencies only

  1. For severe aphids or mealybugs: Vikarsha solution diluted and sprayed on the leaves
  2. Leaf eating caterpillars and grasshoppers: Neem or cow urine as diluted spray, but ideally avoid near the harvest
  3. Leaf miner – ignore unless severe and then use diluted cow urine spray
  4. Viral disease in Papaya: Raw milk solution diluted 1:16 and sprayed on the leaves
  5. Fruit fly: Use phermones in fruit fly trap to eliminate the pests (set up around flowering time)
  6. Leaf hoppers: ?
  7. Shoot and fruit borer: ?